Motion-picture-projecting machine



Jan. 12 1926.

J. D. LAW

Mo'rIoN PICTURE PROJECTING Mmmm'.

Filed August 31. 1921 Patented Jan. 12, 1926. 1,569,287 UNITED STATESPATENT OFFICE.

JOHN DALLAS LAW, F DUNEIDIN, NEW ZEALAND, ASSIGNOR 0F ONE-HALF TO WIL-LIAM FRANCIS JAMES, 0F DUN EDIN, NEW ZEALAND.

' MOTION-PJSCTURE-PROJ ECTIN G MACHINE.

Application filed August 31, 1921. Serial No. 497,296.

To all whom t may concern: l top loop flatten, or should said film orthe Be it known that I, JOHN DALLAS LAW, driving belt break, a contactor contacts imcitizen of the Dominion of New Zealand, and mediatelycloses and completes the electroresident of Dunedin, in the ProvincialDismagnet circuit, whereupon said magnet is trict of Otago, haveinvented certain new energized and attracts its pivoted armature 60 anduseful Improvements in Motion-Picturewhich releases the shutter.Immediately this Projecting Machines, of which the following happens,the shutter, assisted by the spring is a specification. contacts in theelectromagnet and motor cirhis invention relates to pictureprojectcuits, falls between the condensers and the ing machines, whereinmoving films, of an gate thereby preventing the beam of' light 05inflammable nature are employed. from reaching the film. In falling, theshut- In operating such machines, it frequently ter releases the springcontacts in the elechappens that the films stick or break or tromagnetand motor circuits, whereupon both, whereupon they become stationarysaidcontacts open and break both circuits.

and are ignited by the heat` from the beam of Means are also providedwhereby on 70 light from the lamp, the result of which is changing overfrom one machine to another, that not only is damage done to the iilmsand the setting or raising, of thel shutter on one machines, but therisk of fire in places of' e1- machine, causes the shutter on the othermaftertainment and loss of life have to be guardchine to drop. This isaccomplished, by proed against, involving the setting up of elabvidingo-n each machine a contact located in 75 orate and costly precautionarymeasures. the same circuit as the electromagnet of the The main objectof the invention, is thcreother machine, the setting or raising of eachfore, to provide on picture projecting mashutter closing a contact andcompletingr the chines employing moving inflammable films, electromagnetcircuitof the other machine.

safety means, whereby on a film becoming The invention, will however, bemore par- 80 stationary, the beam of light is shut or cut ticularlydescribed with reference to the acoff from the film, said means being somountcompanying drawing wherein ed and adjusted that in operating tobring Figure l shows in elevation a portion of about the above result,they cause the motor a moving picture projecting machine fitted drivingthe machine to be put out of action, with the improvements.k 85 thusrenderingthe machine inoperative and Figure `2 is an enlarged sectionalelevapreventing the film lfrom igniting. tion showing the electromagnetand shutter According to the invention the safety contacts. meanscomprise a pivoted shutter adapted to Figure 3 is a rear view of theplate carbe set or held out of and clear of the beam rying the shuttercontacts. 90 of light by a catch at the end of the pivoted Figure 4 is apart elevation of a centrifuarmature of an electric magnet. The shutgalgovernor provided with means for closter-in its set position, closesseparate spring ing the electromagnet circuit. contacts in the samecircuit as the electro- Figure 5 is a detail view ofa contact formagnet, and in the same circuit as themotor use either in conjunctionwith the film, or 95 which drives the apparatus. the driving belt.

Also in the same circuit as the electromag- Figure 6 illustrates acontact for use in net, are a number of contacts which remain the loopsof the film. open so long as the film is feeding properly Figure 7 showsthe mounting of a contact and the machine is in proper running order. inconjunction with the dr1ving belt, and 100 Some of these contacts arelocated above Figure 8 is a diagram illustrating the wirthe gate of themachine, and in the line of ing.

1 travel of the lilm'as it passes from the feed- The electromagnet'l ishoused in a casing ing s oolto the gate; others are located be- 2,mountedl over the condensers la of the low t e latter and in the line oftravel of machine, and has a pivoted armature 3, the 105 the filml as itpasses from the gate to the outer end of which is formed into a catch 4.windin in spool, while one or more contacts The shutter 5 is hinged soas to be capable are in le line of travel of the belt from the ofdropping between the condensers 1ZL and driving motor to the machine. Ythe gate 6 of the machine, for the purpose Should the film stick in thegate, or the of preventing the beam .of light from the 119 i located inthe same circuit from reaching the film 7 as the latter passes throughthe gate 6. On the shutter 5 is provided a catch 5a adapted to engage,when` the shutter is raised, with the catch 4 of the armature 3, wherebythe latter .retains said shutter in its raised position a ainst the'pressure of spring operated plungers 8, 9 and 10.

These plungers 8, 9 10 pass through a metal plate 11, and also through aplate 12 of insulating material, the plungers 8, 9 each having at theirouter ends, buttons 8a and 9a`of insulating material, and beingpivotally connected at their inner ends tc short levers 14-15 centrallypivoted on th plate 12.

The lower ends of the levers 14, 15 serve as switch blades, which whenthe shutter 5 is raised, make contact with plates 16, 17, respectivelyon the plate 12.

The contact plates 16 are located 1n the same circuit 18, (Figure 8) asthe motor 25 which drives the machine, while the'other pair of contactplates 17 is located 1n the same circuit 19 as the electromagnet 1.

The plunger 10 is made wholly of 1nsulating material and has fixed.bthereon behind the plate 12 a metal collar 1()a having movement betweensaid plate and a loop 13 formed in a metal strip 13 on the rear of theplate 12. The collar 101 is normally forced away from the loop v13, butwhen the shutter 5 is raised and presses against the plunger` 10 itmakes contact with the loop 13a. Y

The metal strip 13 and the collar 10a are as the electromagnet of theother machine, that is when two machines are employed and connected, sothat on raising the shutter 5 of one malamp,

chine the circuit through the electromagnet is closed, the shutter themachine put out of the other machine thereof dropped, and of action.

At suitable points above and below the gate of the machine, rocker arms2O are mounted. Each arm 20, Figure 5, carries at one end a roller 21while its other end is formed into a switch blade capable ofbridgingcontacts 22 located in the electromagnet circuit 19.

The film 7 is passed around these rollers 21, so that its tension whenin running order keeps the switch ends'of the arms 2() from entering thecontacts 22. Should however from any reason the ilm 7 become slack at apoint engaged by a roller 21, or leave the latter, said roller drops andallows the switch end of its arm 2O tov enter and bridge its contacts22, and complete the circuit 19 through the electromagnet 1 whereuponthe latter is energized and attracts its armature 3.

The attraction of the armature 3 results in the catch 4 being liftedclear of the catch 5a of the shutter immediately drops between thecondensers 1.a and gate 6 and shuts off the beam of light from thelatter.

'llie shutter 5 is assisted in its falling movement by the springoperated plungers 8, 9 and 10, which give an initial push to theshutter, and at the same time open the contacts 16 and 17, which resultsin both the motor circuit 18 and the electromagnet circuit 19 beingopened, and the machine rendered inoperative.

Also the plunger 10 by its forward movement draws the metal collar 10ufrom contact with the plate 13n in the circuit of the electromagnet ofthe other machine.

-1clclitionalco1itacts comprising a pair of spring plates 23 alsolocated in the same circuit 19 as the electromagnet 1, are placed in theupper loop 7 of the film 7. These contact plates 23 normally remainapart, but should the loop 7 straighten out more than the desired extentthe plates 23 are forced together and close the electromagnet circuit 19and cause the shutter 5 to drop and the circuits 18, 19 to be opened asbefore described.

Where it is impracticable to mount a rocker arm 20 in the lower loop 7bof the lilm, a pair of spring contact plates similar to the plates 23can be used, for the purpose of closing the electromagnet circuit 19 onthe .oop 7b straightening out more than is desirable.

A rocker arm 20 is also used in conjunction with the driving belt 24,from the motor 25 so that should said belt break or leave its pulleys,the electromagnet -circuit 19 is immediately closed, the shutter 5 isdropped, and the machine brought to a standstill.

Further means for bringing about the dropping of the shutter 5 so as toprevent the beam of light from reaching the film Vin the gate, shouldthe running of the machine fall below normal, are also provided.

These means (Figure 4) consist in using the centrifugal governor atpresent fitted on existing machines, to keep the ordinary tire shutter(dispensed with in this invention) raised, for the purpose of keepingopen contacts located in the electromagnet circuit 19, so long as theAnormal speed of running of the machine is maintained.

This governor 26 the construction of which is well known has connectedto its arm 27, a hanging link 28, the upper end 29 of which carries anadjustable contact 30, while a further contact 31, which with thecontact 3() is located in the electromagnet circuit 19, is alsoprovided.

The arm 27 tends to fly outwards, and while the normal speed of themachine is maintained it forces the lower end of the link 28 outwardsand the upper end 29 of the latter backwards, thereby keeping the 5. Thelatter thereupon lll contacts 30-31 apart. Immediately however the speedof the machine falls below normal, the arm 27 drops and allows the upperend' 29 of the link 28 to move towards the contact 31 so that thecontact 30 will touch same and so close the electroma et circuit 19.

urrent for any of the circuits can be drawn from any suitable source. r

What I do claim and desire to obtain by Letters Patent of the UnitedStates of America is 1. In a vmotion picture projecting machine, ashutter mounted so as to be capable of dropping between the condensersand the gate; an electromagnet having an armature provided with a catchfor keeping the shutter raised; contacts controlled by the film and themachine driving belt for closing the electromagnet circuit; and contactsclosed and allowed to open by the raising and dropping respectively ofsaid shutter, .for closing and breaking the motor and the electromagnetcircuits. l

2. -In a motion picture projecting apparatus, a first machine, a pivotedshutter with a catch thereon; an electromagnet having a pivoted armatureprovided with a catch for engaging the catch of the shutter; contactscontrolled by the film and the machine driving belt for closing theelectromagnet circuit; a plurality of plungers connected to switch bladearms, springs for said plungers, the plungers being pressed against theaction of said springs by said shutter when raised,

to make contact with plates in the motor and the electromagnet circuit;a second machine, and another plunger pressed against the action ofanother spring when the shutter is raised, for closing the electromagnetcircuit of said second machine.

3. 'In a motion picture projecting machine, an electromagnet having "anarmature, a shutter, said armature holding said shutter raised, attimes, contacts in the electrical circuit of the electromagnet, andlocated in a loo of film and adapted to be brought toget 1er by thestraightening out of said loop.

4. In a motion picture projecting machine, a centrifugal governor, anarm connected therewith and having a pivoted link, an electric contactcarried by said link, a fixed electrically connected contact; and anelectromagnet having an armature adapted to retain a shutter out of thebeam of light .to the rfilmf, the circuit of said'electromagnetincluding. both of said contacts.

5; In a motion picture projecting machine, a motor, an electromagnethaving a plvoted amature withacatch thereon; a pivoted shutter with acatch thereon; spring operated plungers insulated from said shutter,levers connected with said plungers and having switch blades at theirends, a pair of contacts in the machine motor circuit, both mounted onan insulated plate, said switch blades and pairs, of contacts,cooperating to regulate the machine.

6. In a motion picture projecting apparatus, a first machine, a-motorfor the same,

' an electromagnet having a pivoted armature with a catch thereon; apivoted shutter with a catch thereon; a pair of spring operated plungersinsulated from said shutter, and connected with separate levers havingends which act as switch blades; a pair of `contacts in theelectromagnet circuit and a' pair of contacts in the machine motorcircuit, both being mounted on an insulatedplate, a second projectingmachine, another spring operated plunger insulated from said shutter andcarrying an electrically connected contact adapted to be moved againstan electricallyconnected strip on said insulated plate, the contact onsaid plunger and said strip being both in an electromagnet circuit ofsaid second machine.

7. In a motion picture projecting a' paratus, a first machine, anelectromagnet aving anarmature with a catch 'thercon; a shutter kept ina raised position b said catch, a second machine having an eectromagnet, and a plunger operated by the raising of said shutter toclose the electromagnet circuit of said second machine.

8. In a motion picture projecting apparatus, a first machine, anelectromagnet havlng an armature with a catch thereon; a shutter kept ina raised position by said catch; a second machine having anelectromagnet, and a spring pressed plunger associated with the firstmachine and carrying an electrically connected contact for closing thecircuit of the electromagnet of the second machine. l.

9. In a motion picture projecting apparatus, a first machine, anelectromagnet havin a pivoted armature with a catch thereon; a hingedshutter adapted to be kept in a raised position by chine having `anelectromagnet, said shutter, when raised, closing the circult of theelectromagnet of said second-machine.

Si ed at, city of Dunedin, in the Provincial listrict of Otago, Dominionof New Zealand, this 21st day of June 1921.`

JOHN DALLAS LAW.

said catch, a second ina-`

